With growing concern about the protection of soil quality and biodiversity many countries have established regional and national programmes to monitor soil quality. This book reviews the theory and practice of a range of the various microbiological methods used within these programmes. The first section gives an overview of approaches to monitoring, evaluating and managing soil quality. The second section provides a practical handbook with detailed descriptions of the methods. The methods are described in chapters on: soil microbial biomass and numbers, soil microbial activity, soil microbial diversity and community composition and plant-microbe interactions and soil quality. Finally, a census is given of the main methods used in over 30 European microbiological laboratories.